1. Field of the Invention
The present invention relates to an exposure apparatus, a device manufacturing method and an environmental control of an exposure apparatus. More particularly, the present invention relates to an exposure apparatus used in a lithography process in manufacturing semiconductor devices, liquid crystal display devices and the like, a device manufacturing method in which exposure is performed by using the exposure apparatus, and an environmental control method to keep environmental conditions inside an exposure chamber of the exposure apparatus substantially constant.
2. Description of The Related Art
In an apparatus performing processing for fine features such as a semiconductor exposure apparatus, an air conditioning system is provided to adjust temperatures therein because the temperatures need to be adjusted with extremely high accuracy. In this case, the air conditioning system needs to be a circulating system since very precise temperature adjustment needs to be performed within a range of, for example, xc2x10.1xc2x0 C. relative to a target temperature. Accordingly, a blower is required for circulating air. In the exposure apparatus, a machine chamber housing an air conditioner including the blower is normally installed independently of a main body chamber housing an exposure apparatus main body because of problems of vibration and the like.
In the exposure apparatus that manufactures electronic devices such as LSI""s and the like, pressure inside the main body chamber housing the exposure apparatus main body, which consists a reticle, a projection lens and the like, is usually set to be higher than that of the outside of the main body chamber. The air inside the main body chamber leaks to the outside due to a pressure difference between the inside and the outside of the main body chamber, air needs to be supplied from the outside to compensate for the lost air. Accordingly, an outside air inlet called an OA port is provided in part of a supply path of the air (a supply path) to the main body chamber, and outside air is normally, naturally fed through the OA port.
On the other hand, the air that has returned from the main body chamber enters the air conditioner in the machine chamber together with supply air from the outside. The air that has entered the air conditioner is cooled down by a cooler. At this point, excess moisture brought from the outside by the feeding of the outside air condenses on the radiation fins of the cooler and so is removed. Then, the air from which the excess moisture has been removed is heated to a given temperature by a heater, and sent into the main body chamber by the blower.
In addition, it has recently been found out that trace level gas in a clean room atmosphere has adverse effects on a semiconductor manufacturing apparatus such as a reduction projection exposure apparatus (a stepper) and the like. More specifically, in an excimer laser exposure apparatus, an X-ray exposure apparatus or an electron beam exposure apparatus, which uses an excimer laser such as a KrF excimer laser, an ArF excimer laser or the like as a light source, a high sensitive chemically amplified resist is used in order to compensate for insufficient brightness of the light source. The chemically amplified resist contains an acid-generating agent as a photosensitive agent, and acid generated by the agent upon exposure induces catalytic reaction in a subsequent thermal processing (PEB: post exposure bake) so as to make the exposed part of the resist insoluble (a negative type) or soluble (a positive type) in a developing solution. However, in the case of a positive resist, trace level basic gas of a ppb level in the atmosphere may neutralize acid catalyst generated on the surface of the positive type chemically amplified resist to form a hardly-soluble surface layer. In such a case, the phenomenon occurs that after being exposed and developed, a cross section of the resist, which should be rectangular, is made into a shape like a letter T (referred to as a T-shape) When such a hardly-soluble surface layer is formed, the benefit of using the chemically amplified resist, which is a high sensitive resist, is lost. In order to proceed to exposure, overcoat or the like is necessary, which reduces throughput.
Further, as the exposure light becomes shorter in wavelength and more intense in illuminance, the phenomenon also occurs that trace level gas in the atmosphere precipitates as tarnish substances, which adhere to the surfaces of optical members forming an illumination system. Such a phenomenon occurs due to photochemical reaction between the trace level gas in the atmosphere and the exposure light. Reactive substances are ammonia gas, sulfur oxide, organic silicon compound and the like in the air. As a result of generation of tarnish on the optical members forming the illumination system, the illuminance is greatly reduced so that the throughput is reduced.
Therefore, means for removing a trace of impurity gas in a clean room atmosphere are disclosed in, for example, Japanese Patent Laid-Open No. 6-77114 and the U.S. Pat. No. 5,430,303 corresponding thereto.
With respect to conventional exposure apparatuses, a method where an exposure apparatus main body, and a substrate transportation system transporting a photosensitive substrate such as a wafer or a mask transportation system are housed in one environmental control chamber, and another method where the exposure apparatus main body, and the substrate transportation system or the mask transportation system are housed in different environmental control chambers are known.
In both methods, either one of the following techniques has been adopted. One is that air is blown into the inside of the exposure chamber that houses the exposure apparatus main body sideways (side-flow) from the side other than a side where the substrate transportation system and the mask transportation system are installed, and the other one is that air is blown downward (down-flow) from the ceiling to the floor of the exposure chamber.
According to the invention disclosed in the foregoing Japanese Patent Laid-Open, a trace of impurity gas in a clean room atmosphere can be surely removed to a certain extent, and reduction in illuminance due to tarnish on the optical members and generation of the hardly-soluble surface layer of the chemically amplified resist can be limited.
Recently, however, as the feature sizes of semiconductor devices become finer, outgas from an adhesive agent, a sealing agent, paint and components used in exposure apparatuses, which caused no problem in the past, is coming to pose problems that cannot be ignored, and the exposure apparatus main body itself can be regarded as a source of contamination. To get rid of influences of the outgas, the insides of an exposure apparatuses are required to be chemically clean, and chemical filters to remove chemical substances are commonly installed in exposure apparatuses similarly to the invention disclosed in the foregoing Japanese Patent Laid-Open.
However, in a conventional exposure apparatus, since a filter that removes impurities is provided only at the outside air inlet or a supply path to the inside space of the main body chamber; chemically contaminated air containing outgas released from the exposure apparatus main body when performing air conditioning thereof returns to an air conditioner and then is sent into the chemical filter disposed in the supply path by a blower of the air conditioner. Accordingly, the lifetime of the chemical filter in the supply path shortens particularly, and the chemical filter must be frequently replaced with a new one. Further, design of the conventional exposure apparatus has made on the presupposition that replacement of the chemical filter is unnecessary during the life of the apparatus. That is, replacement of the chemical filter itself has never been taken into consideration. Therefore, a chemical filter other than the one at the outside air inlet is normally disposed in a position where replacement is difficult, and thus it takes a long time to replace the filter. Furthermore, since the door of the chamber must be kept open for a long time for replacing the chemical filter, chemically unclean air in the clean room outside the apparatus enters the apparatus, and it is difficult to maintain high cleanliness of the inside space.
Further, in the conventional exposure apparatus, a drain pipe is essential for temperature adjustment, and the drain pipe makes the air-conditioning portion of the apparatus open to the outside. Moreover, a heater and a cooler are often installed immediately before the blower in the structure of the apparatus, and pressure of the space around a drain pan is lower (by about xe2x88x923 hPa) than that of the outside atmosphere due to a characteristic of the blower. Accordingly, the following unfavorable phenomena xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 may occur.
a. The drain pipe finally comes to be connected with other apparatuses in a semiconductor manufacturing factory, and pressure of the space around the drain pan is lower than that of the outside atmosphere. Therefore, impurity gas released from other manufacturing apparatuses may flow into the exposure apparatus via the drain pipe when the drain pan is not filled with water.
b. Chemical substances released into the atmosphere of each apparatus in chemical processes such as alkaline processing and acid processing performed in other manufacturing apparatuses dissolve into wastewater after use for temperature adjustment of each apparatus in a microscopical level. There is large possibility that the chemical substances flow into the exposure apparatus in a ppb level via the drain pipe. In many cases, no particular measures are taken for chemical contamination as long as the waste water flowing in a pipe line system does not contain chemical substances at high concentration. Furthermore, the pipe line system for wastewater after use for temperature adjustment may be communicated to a clean room outside the exposure apparatus.
c. There is a case where some water due to condensation of the cooler is in the drain pan depending on installation conditions of the exposure apparatus. In such a case, although the outside air does not enter the apparatus directly through the pipe line system, it may enter the apparatus indirectly through the water in the pan, which is not preferable either.
d. Even if the influence of the pipe line system is small, since the water in the drain pan does not flow out due to the influence of the lower pressure, the pan could be a secondary supply source of gas having adverse effects on the exposure apparatus because microbes and the like proliferate after a trace of gas in circulating air dissolves into the water and is condensed.
In addition, in an exposure apparatus that uses the foregoing conventional side-flow technique as the air conditioning technique in the exposure chamber, two or three side faces, i.e. the face of a side where the substrate transportation system or the mask transportation system is installed, the face of a side where a blow port that sends gas for air conditioning into the exposure chamber is disposed, and further, depending on the case, the face of a side where a machine chamber having the air conditioner therein is arranged, of the four side faces (right, left, front and rear) of the exposure chamber are necessarily blocked. In this case, maintenance of the exposure apparatus main body can only be performed from either side of two predetermined sides or a predetermine side, and the maintenance operation may be difficult depending on the shape and size of the empty space in the clean room where the exposure apparatus is installed.
On the other hand, in an exposure apparatus that uses the foregoing conventional down-flow technique, the maintenance operation of the exposure apparatus main body can be performed from three or two side faces other than the face of a side where the substrate transportation system or the mask transportation system is installed, or this side face and the face of a side where the machine chamber is arranged. However, the exposure apparatus of this technique needs a filter for removing dust (an air filter), a chemical filter and a plenum duct of the filter for removing dust. For this reason, the total height of the exposure apparatus increases, and thus the ceiling height of an expensive clean room (factory) in which the exposure apparatus is installed increases so that the equipment cost increases.
Against such background, a new exposure apparatus that contributes to improvement of productivity of micro-devices in terms of the capability of maintaining chemical cleanliness of the atmosphere inside the apparatus, processing capacity and the equipment cost is expected.
The present invention has been created under such circumstances, and its object is to provide an exposure apparatus and a device manufacturing method that can improve the productivity of the microdevice, and an environmental control method of the exposure apparatus.
According to the first aspect of this invention, there is provided a first exposure apparatus, comprising: an exposure apparatus main body that transfers a predetermined pattern onto a substrate; an exposure chamber that houses at least a part of the exposure apparatus main body, and in which environmental conditions are kept substantially constant; an air conditioner that performs air conditioning inside the exposure chamber; a machine chamber that houses at least a part of the air conditioner; a supply path of gas for air conditioning supplied from the machine chamber into the exposure chamber; a first chemical substance removing filter arranged in part of the supply path; an exhaust path that forms a path of the gas for air conditioning that returns to the machine chamber from the exposure chamber; and a second chemical substance removing filter arranged in part of the exhaust path to remove chemical impurities in the gas for air conditioning.
With this apparatus, the air conditioner arranged in the machine chamber supplies the gas for air conditioning via the supply path, and air conditioning inside the exposure chamber is performed. Then, the gas for air conditioning that has performed air conditioning returns to the machine chamber via the exhaust path. Here, the first chemical substance removing filter is arranged in part of the supply path, and the second chemical substance removing filter is provided in part of the exhaust path of the gas for air conditioning that returns to the machine chamber from the exposure chamber. Accordingly, prior to sending the gas for air conditioning into the exposure chamber (space housing at least a part of the exposure apparatus main body) by the air conditioner in the machine chamber, the first chemical substance removing filter arranged in part of the supply path removes chemical contaminants in the gas for air conditioning and the second chemical substance removing filter substantially securely removes contaminants, which are contained in the gas for air conditioning returning to the machine chamber from the exposure chamber and which were outgassed in exposure apparatus main body. As described, the inside of the exposure chamber can be kept highly, chemically clean, and thus occurrence of a problem such as illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a long period of time. Therefore, highly accurate exposure quantity control and thus highly accurate exposure can be performed for a long period of time, increase of exposure time due to the illuminance reduction is effectively suppressed to maintain high throughput for a long period of time, and thus the productivity of micro-devices can be improved. Furthermore, since chemically clean gas for air conditioning, from which chemical contaminants have been removed by the second chemical substance removing filter arranged in part of the exhaust path of the gas for air conditioning returning to the machine chamber from the exposure chamber, is sent into the first chemical substance removing filter arranged in part of the supply path, the lifetime of the first chemical substance removing filter lengthens and replacement is not needed for a long period of time.
In the first exposure apparatus according to the present invention, it is desirable that the exposure chamber and the machine chamber be severally formed inside different chambers. In terms of vibration caused by the air conditioner in the machine chamber, the machine chamber is normally arranged independently of the exposure chamber. Further, in this case, since the exposure chamber and the machine chamber are formed in the different chambers and the chemical substance removing filter is arranged in part of the exhaust path returning to the machine chamber from the chamber where the exposure chamber is formed, the chemical substance removing filter can be readily replaced. Accordingly, the down time of the apparatus during replacement of the chemical substance removing filter shortens, and the processing capacity can be improved in the long term.
In this case, the exposure chamber and the machine chamber may be arranged close to each other on the floor, and the exposure chamber and the machine chamber may be connected with each other via a freely detachable connection unit.
Further, it is desirable that the connection unit be one to prevent the vibration caused in the air conditioner from transmitting to the exposure chamber, and for example, it may be constituted by an expandable and contractable bellows-like member. In such a case, since the vibration caused by the air conditioner in the machine chamber is absorbed by expansion of the bellows-like member that constitutes the connection unit, influences of the vibration on the exposure chamber can be reduced. Accordingly, reduction of exposure accuracy is suppressed and the yield of micro-devices can be improved as a result, and thus the productivity can also be improved.
In the first exposure apparatus according to the present invention, when the exposure chamber and the machine chamber are arranged close to each other on the floor and both of them are connected with each other via the freely detachable connection unit, the first chemical substance removing filter may be arranged in the vicinity of the connection unit. In such a case, the chemical substance removing filter arranged near the connection unit can be easily replaced after removing the connection unit, if necessary.
In the first exposure apparatus according to the present invention, the exposure chamber and the machine chamber may be formed in a same chamber. As described above, in terms of the vibration caused by the air conditioner in the machine chamber, the machine chamber is normally arranged independently of the exposure chamber. However, since the problem of vibration can be solved with another means, the exposure chamber and the machine chamber may be formed by dividing one chamber with a partition.
In the first exposure apparatus according to the present invention, the machine chamber may be provided with an outside air inlet, and the exposure apparatus may further comprise a third chemical substance removing filter arranged in a path of air that is taken in through the outside air inlet. In such a case, air in the clean room where the exposure apparatus is installed is taken into the apparatus. Since the chemical substance removing filter is provided in the path of the air taken in, air from the outside, which has been cleaned, is taken into the apparatus so that cleanliness inside the apparatus is not reduced. Therefore, the pressure inside the exposure chamber can be kept higher than that of the outside atmosphere to maintain high cleanliness.
In the first exposure apparatus according to the present invention, the entire supply path and the entire exhaust path for the air-conditioning gas is preferably made of a material outgassing less. Particularly, part of the supply path that is downstream of the first chemical substance removing filter is preferably made of a material outgassing less. In such a case, since little outgas is released in the supply path downstream of the first chemical substance filter arranged in part of the supply path, chemically clean gas for air conditioning can be sent into the exposure chamber (space that houses at least a part of the exposure apparatus main body).
In the first exposure apparatus according to the present invention, when the first chemical substance removing filter is arranged in part of the supply path, the supply path may be divided into a plurality of paths in the downstream of the first chemical substance removing filter arranged in part of the supply path, and each of the plurality of paths may be connected to a respective chamber of a plurality of different chambers including the exposure chamber.
In this case, each of the plurality of paths is preferably provided with an air filter to remove particles in the vicinity of a blow port of the gas for air conditioning to each of the plurality of different chambers. In such a case, since the exposure apparatus can be installed in a clean room having relatively low cleanliness of class about 100 to 1000, the maintenance cost of the clean room can be reduced.
In the first exposure apparatus according to the present invention, the air conditioner includes a cooler that cools the gas for air conditioning that circulates within the machine chamber, and a heater that heats the cooled gas, and the exposure apparatus may further comprise a controller that controls the surface temperature of the cooler so that condensation does not occur. In such a case, since the controller controls the surface temperature of the cooler to a temperature where condensation does not occur, the drain pipe system of the air conditioner is not needed. Accordingly, occurrence of problems such as the foregoing xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 caused by the presence of the drain pipe system can be prevented; the insides of the machine chamber and the exposure chamber are chemically cleaner, and thus occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a even longer period of time.
According to the second aspect of this invention, there is provided a second exposure apparatus, comprising: an exposure apparatus main body that transfers a predetermined pattern onto the substrate; an exposure chamber that houses at least a part of the exposure apparatus main body, and in which the environmental conditions are kept substantially constant; a machine chamber connected to the exposure chamber via a supply path and via an exhaust path; an air conditioner arranged in the machine chamber that includes a cooler to cool gas for air conditioning circulating within the machine chamber and that performs air conditioning inside the exposure chamber; and a controller that controls the surface temperature of the cooler so that condensation does not occur.
According to this, since the controller controls the surface temperature of the cooler to a temperature where condensation does not occur, the drain pipe system of the air conditioner is not needed. Accordingly, occurrence of problems such as the foregoing xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 caused by the presence of the drain pipe system can be prevented; the insides of the machine chamber and the exposure chamber are chemically cleaner, and thus occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a longer period of time. Therefore, highly accurate exposure quantity control and thus highly accurate exposure can be performed for a long period of time; increase of the exposure time due to the illumination reduction is effectively suppressed to maintain high throughput for a long period of time, and thus the productivity of micro-devices can be improved.
In the second exposure apparatus according to the present invention, the air conditioner may further include a heater that is arranged in the machine chamber and that heats the cooled gas. In such a case, the temperature of the air-conditioning gas can be easily adjusted to a desired temperature by heating the gas, which has been cooled by the cooler, by the heater.
The second exposure apparatus according to the present invention may further comprise a drain pan arranged below the cooler in a direction of gravity. In such a case, when controlling the surface temperature of the cooler becomes difficult due to occurrence of some problem in the cooler, the controller or the like, some measures are available.
According to the third aspect of this invention, there is provided a third exposure apparatus, comprising: an exposure apparatus main body that transfers a pattern formed on a mask onto a substrate; an exposure chamber that houses the exposure apparatus main body; and another chamber constituting an environmental control chamber separate from the exposure chamber and arranged on a side of the exposure chamber, wherein a blow port of gas for air conditioning supplied into the exposure chamber is provided in a boundary area between the exposure chamber and said another chamber.
According to this, since a blow port of gas for air conditioning supplied into the exposure chamber is made in a boundary area with the exposure chamber in another chamber, maintenance of the exposure apparatus main body in the exposure chamber can be performed from three sides other than a side, where the blow port is made, among the four sides (front, rear, right and left) of the exposure chamber. Accordingly, working efficiency of maintenance improves to shorten the time required for the maintenance, which can shorten the down time of the apparatus due to the maintenance. Furthermore, since the inside of the exposure chamber is air-conditioned by the gas for air conditioning blown from the blow port made in a boundary area with said another chamber, for example, in the upper half portion of the exposure chamber, there is no need to provide a filter for removing dust (air filter), a chemical filter and the plenum duct of the filter for removing dust on the ceiling of the exposure chamber. Therefore, according to the third exposure apparatus of the present invention, the cost of the clean room can be reduced because the total height of the apparatus can be lowered while securing good maintenance performance. Thus, the productivity of micro-devices can be improved due to improvement of the processing capacity in the long term and reduction of the equipment cost.
In the third exposure apparatus of the present invention, the inside of the exposure chamber may be air-conditioned in the down-flow manner using the gas for air conditioning blown from the blow port provided in the boundary area, or the upper space of the exposure chamber may have the gas blown into it in the side-flow manner.
The third exposure apparatus according to the present invention may further comprise a mask transportation system housed in said another chamber, which transports a mask into the exposure apparatus main body and transports the mask from the exposure apparatus main body.
Incidentally, in recent years there has been a demand for substrates (e.g., wafers in the manufacturing of semiconductor devices) of a larger size for the purpose of improving the productivity. The substrate side inclines to become large compared to the mask side, and in an exposure apparatus the substrate transportation system inclines to become larger than the mask transportation system. The third exposure apparatus according to the present invention was made to deal with this point as well.
The third exposure apparatus according to the present invention may further comprise an air filter to remove particles, which is arranged on the side of the blown port opposite said another chamber. As described, the substrate transportation system inclines to be relatively larger than the mask transportation system. Accordingly, since a mask transportation system housing chamber (said another chamber) has empty space to spare larger than that of a substrate transportation system housing chamber, an air filter can be arranged therein easily. In this case, with the air filter, a filter plenum (a chamber behind the filter for converting the dynamic pressure of sent gas into static pressure and blowing the gas uniformly) may be arranged. By this, uniform air-flow can be obtained from the blow port.
The third exposure apparatus according to the present invention may further comprise a chemical substance removing filter arranged in the exhaust path of the gas for air conditioning that returns from the exposure chamber to an air conditioner for the exposure chamber. In such a case, since the apparatus comprises the chemical substance removing filter arranged in the exhaust path of the gas for air conditioning that returns from the exposure chamber to its air conditioner, the chemical substance removing filter can substantially securely remove contaminants outgassed in the exposure apparatus main body, and thus the inside of the exposure chamber can be kept highly, chemically clean. Accordingly, occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a longer period of time.
In this case, the air conditioner may include a cooler that cools the gas for air conditioning, and the exposure apparatus may further comprise a controller that controls the surface temperature of the cooler so that condensation does not occur. In such a case, the controller controls the surface temperature of the cooler to a temperature where condensation does not occur. Accordingly, the drain pipe system of the air conditioner is not needed, and occurrence of problems such as the foregoing xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 caused by the presence of the drain pipe system can be prevented. As a result, the inside of the exposure chamber is chemically cleaner, and thus occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a longer period of time.
In the third exposure apparatus according to the present invention, supply paths and exhaust paths are constructed and arranged for the exposure chamber and said another chamber such that air conditioning thereof is performed by the same air conditioner. In such a case, each chamber can be air conditioned efficiently using only a single air conditioner.
In the first to third exposure apparatuses according to the present invention, the exposure apparatus main body may include a substrate stage that holds the substrate and an interferometer that measures a position of the substrate stage, and the exposure apparatus may further comprise another air conditioner that performs air conditioning of a part of the space inside the exposure chamber, where the substrate stage and the interferometer are arranged, independently of the air conditioner. In such a case, using an air conditioner having high temperature controllability as said another air conditioner limits measurement error of the interferometer caused by a so-called air fluctuation (temperature fluctuation) as small as possible, and positional control of the substrate stage, which requires accuracy particularly, can be performed with required accuracy.
In this case, said another air conditioner may be separate from the air conditioner, but, not being limited to this, may share a part of the air conditioner.
In the first to third exposure apparatuses according to the present invention, a surface of said substrate may be coated with a chemically amplified resist as a photosensitive agent. In such a case, since the inside of the exposure chamber can be kept chemically clean, the illumination reduction due to tarnish of the optical elements can be suppressed for a long period of time, and additionally, generation of the hardly-soluble surface layer of the chemically amplified resist can be limited.
Further, performing exposure in the lithography process by using any of the first to third exposure apparatuses according to the present invention improves the productivity of highly integrated devices in terms of at least any one of the capability of maintaining chemical cleanliness of the atmosphere inside the apparatus, improvement of the processing capacity in the long term, and reduction of the equipment cost. Therefore, according to the fourth aspect of this present invention, there is provided the device manufacturing method using an exposure apparatus of the present invention.
According to the fifth aspect of this invention, there is provided a first environmental control method of an exposure apparatus that supplies gas at least the temperature of which is controlled into an exposure chamber that houses at least a part of an exposure apparatus main body such that environmental conditions are kept substantially constant inside said exposure chamber, said exposure apparatus main body transferring a predetermined pattern onto a substrate, wherein chemical impurities in said gas are removed in an exhaust path from said exposure chamber, and at least part of said gas from which said chemical impurities have been removed is supplied into said exposure chamber via a chemical substance removing filter.
According to this method, chemical impurities in gas are removed in the exhaust path from the exposure chamber, and at least part of the gas from which the chemical impurities have been removed is supplied through a chemical substance removing filter into the exposure chamber again. Thus, the inside of the exposure chamber can be kept highly, chemically clean, and thus occurrence of problems such as the illumination reduction due to tarnish of the optical elements can be effectively limited for a long period of time. Therefore, highly accurate exposure quantity control and thus highly accurate exposure can be performed for a long period of time; increase of exposure time due to the illumination reduction is effectively limited to maintain high throughput for a long period of time, and as a result, the productivity of micro-devices can be improved.
In the first environmental control method according to the present invention, the surface temperature of a cooler for the gas may be set at such a temperature that condensation does not occur. In such a case, since the surface temperature of the cooler is set at a temperature where condensation does not occur, the drain pipe system of the cooler is not needed. Accordingly, occurrence of problems such as the foregoing xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 caused by the presence of the drain pipe system can be prevented; the insides of the exposure chamber are chemically cleaner, and thus occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a longer period of time.
According to the sixth aspect of this invention, there is provided a second environmental control method of the exposure apparatus that supplies gas at least the temperature of which is controlled into an exposure chamber that houses at least a part of the exposure apparatus main body such that environmental conditions are kept substantially constant inside the exposure chamber, the exposure apparatus main body transferring a predetermined pattern onto a substrate, wherein the gas is made to pass though a cooler before supplying the gas into the exposure chamber and the surface temperature of the cooler is set at such a temperature that condensation does not occur.
According to this, the gas passes through the cooler before being supplied into the exposure chamber, and the surface temperature of the cooler is set at a temperature where condensation does not occur. Therefore, the drainpipe system of the cooler is not needed, and occurrence of problems such as the foregoing xe2x80x98axe2x80x99 to xe2x80x98dxe2x80x99 caused by the presence of the drain pipe system can be prevented. Accordingly, the insides of the exposure chamber are chemically cleaner, and thus occurrence of problems such as the illuminance reduction due to tarnish of the optical elements can be effectively suppressed for a longer period of time. Therefore, highly accurate exposure quantity control and thus highly accurate exposure can be performed for a long period of time; increase of exposure time due to the illumination reduction is effectively limited to maintain high throughput for a long period of time, and as a result, the productivity of micro-devices can be improved.
According to the seventh aspect of this invention, there is provided an exposure apparatus, comprising: an exposure apparatus main body that transfers a predetermined pattern onto a substrate; a substrate transportation system that transports the substrate to the exposure apparatus main body; a first chamber that houses at least a part of the exposure apparatus main body and in which environmental conditions are kept substantially constant; a first return duct an end of which is connected to the first chamber and through which gas exhausted from the first chamber passes; a second chamber that houses at least a part of the substrate transportation system, and in which environmental conditions are kept substantially constant; a second return duct an end of which is connected to the second chamber and through which gas exhausted from the second chamber passes; and a first chemical substance removing filter that is connected to another end than the end of the first return duct and to another end than the end of the second return duct and that removes chemical impurities in both of gas exhausted from the first chamber and gas exhausted from the second chamber.